Jeanine Cummins wants more than anything in the world to give a voice to people who are unable to speak for themselves.

In the past, she has spoken for family members. In her 2004 memoir, "A Rip in Heaven," Cummins spoke for her cousins, Julie and Robin Kerry, who were gang-raped and murdered in 1991. She spoke for her older brother, Tom, who also was hurt in that attack on a bridge outside St. Louis.

"My cousin, Julie was a really gifted writer," says Cummins, 38, who grew up in Gaithersburg.

"She was four years older than I was, and she was a role model I always wanted to emulate. After she died, I think I felt a deep responsibility. I felt that I had to write because Julie's voice was taken from the world a lot sooner than it should have been. But, after I published the memoir, I knew I could never write nonfiction again. It was just too painful."

After graduating from Towson University, Cummins moved to Queens and began writing novels that exposed social injustice and that also drew on her Irish heritage. "The Outside Boy," which she published in 2010, is set in Ireland in 1959 and deals with the plight of a marginalized social group, the Pavee gypsies.

And her new novel, "The Crooked Branch" juxtaposes scenes set in 1840s Ireland's great potato famine with a present-day narrative.

Majella is struggling with post-partum depression when she finds a diary kept by her great-great grandmother. What she learns about Ginny Doyle, who resorts to desperate measures to keep her children from starving, causes Majella to question her own maternal instincts.

Cummins will read from her new book Tuesday at the Ivy Bookshop. During a recent phone chat, she talked about how she uses her own life for inspiration, whether she's writing about a real-life crime or finding the humor in a toxic mommy meet-up group.

How's your brother doing today? The attack would have been difficult enough to cope with, even if he hadn't briefly been falsely accused of the murders.

When he got out of the river, he flagged down the cops, but they didn't believe him. After he spent several days in jail, they found a flashlight on the bridge, and fingerprints on the flashlight. They picked up all four men. They pointed fingers at one another, but they essentially corroborated Tom's story. [The four men were later convicted in the attack,]

Tom has had many, many years of therapy with a wonderful woman in Montgomery County who specializes in survivors of violent crimes and post-traumatic stress. She basically saved his life.

My brother struggles with survivors' guilt and all kinds of ugly stuff. But, he made a decision years ago that he wasn't going to give up on life, that he would be fully engaged. I don't know how he does it, but he does. He is a Rockville firefighter. He has a beautiful wife, and three children, and a sense of humor. He's just amazing — though he's also incredibly annoying pretty much all the time, just like all big brothers.

I admire you for refusing to sell the movie rights to "A Rip in Heaven."

After the book came out, I got offers to buy the movie rights from all over the place, from Brad Pitt and Sony — you name it. But I just couldn't do it. I don't feel like I had a choice in the matter. It would have been very painful for my family.

But I've written two novels since then, and boy, would I like to sell the movie rights to them. That is the way for a writer to make money. But where are the movie offers now? If someone out there is interested in making a movie from one of my novels, please, don't hold back.

What about the potato famine particularly interested you?

I lived in Belfast for two years after college, and I came to realize that the Irish famine affected every family. By the most conservative estimates, at least a quarter of the population — about 2 million people — either left Ireland aboard the coffin ships or starved.

Very few Americans know that the famine was entirely preventable. There was just one potato crop that failed. There was plenty of food being exported from Ireland the entire time the local population was starving.

There was one landlord who lived in County Mayo and who just decided that no one on his land would starve. And, they didn't. He didn't take in any rents that year, but he didn't lose a single tenant. One hundred fifty years later, they still sing songs about him. That should have happened all over Ireland.

It should be happening in Somalia today. In this global economy, there's no reason for anyone to starve.

In your book, you describe a land agent who literally steps over the bodies of people starving outside his gates rather than give them a bite to eat. It's hard to comprehend that degree of callousness.

I don't understand it myself. There were a lot of laws that England had imposed at the time that kept the Irish people oppressed. They weren't allowed to speak their own language, weren't allowed to own property that was valued over a certain amount.

At the time, the landowners weren't Irish, but English. Most of them never set food in the country, let alone on their property. So, they were removed from the famine. They didn't see it first-hand.

There also was a lot of talk in Parliament at the time about the famine being divine providence. The population of Ireland had grown dramatically over the past century, and they felt this was God's way of culling the Irish and taking care of the problem.

Let's talk now about the scenes set in the present day. Did you, like Majella, have a difficult time adjusting to being a new mom?

Motherhood is always hard. That's one of the things that took me by surprise. I loved kids, I wanted kids, I was good with kids — and suddenly, I was home alone with this tiny, crying baby.

A few years ago we had this Yummy Mummy thing. New mothers were supposed to have the perfect manicure, and go to their hairdressers twice a week with their babies were on their hip. The fact is, you're covered in spit and poop, and your body isn't what it was a year ago and you're exhausted. Mothers should be able to admit that without shame and support one another instead of being so judgey and competitive with one another.

Did you exaggerate when you wrote the section about the Mean Mommy meet-up group?

Unfortunately, no. I went once to the meet-up and never went back. It was horrible. There were all these warring cliques: the SAH [stay at home] moms versus the working moms, the breast-feeding moms versus the formula moms. I just couldn't believe the way these women were treating each other.

One of the mothers of a 2-year-old actually said to me, "I don't even bother talking to the mothers of the newborns because I don't have anything in common with them."

I thought, "You are both women in your 30s with young children who are living in Queens. What more in common could you have that that?"